Current imaging devices, such as a digital still camera (DSC) include a picture-taking mode in which a “liveview” video image is displayed on a color LCD. The liveview image is provided in order to facilitate the framing and capturing of an image. In this picture-taking mode, it is desirable that the liveview image looks as natural as possible to a user of the DSC. In order to provide a displayed view that is as close as possible to a liveview, e.g., a view of an object that a human being would see with a naked eye, parameters such as the DSC's video frame rate (so that motion is displayed in a realistic manner), image lag (so that motion is not delayed before it is displayed), color balance (e.g., color hue or hue), and tonal reproduction (e.g., brightness and contrast) of the image need to be controlled.
Conventionally, correcting an image (e.g., correcting the color hue, contrast and brightness), while maintaining a high video frame rate and minimal image lag, typically involves using either a dedicated liveview hardware pipeline (i.e., data processing circuitry that performs white balance correction, pixel demosaicing, color matrixing, and tone correction operations) or by employing a high performance microprocessor such as a digital signal processor (DSP) in order to manipulate all the data of the liveview image frames in a manner similar to that performed by the hardware pipeline. For imaging devices that do not contain either a dedicated liveview hardware pipeline or a DSP, the liveview frame rate and image lag, and hence displayed image quality typically suffers.
Additionally, in very low light situations, liveview video may require an increase in image device exposure time (e.g., length of time a charged coupled device (CCD) is exposed to the scene). The increased exposure time is necessary in order to maintain a sufficiently bright liveview image on a display of the device. As exposure time is increased beyond a certain point; however, the frame rate must accordingly be reduced proportional to the exposure time. A result of this reduction in frame rate is a less realistic video product.